Drill bit



23, 1963 c. M. KUCERA ETAL 3,385,385

DRILL BIT Filed April 1, 1966 55 Sheets-Sheet l 1968 c. M. KUCERA ETAL 3,385,385

1NVENTOR5 5 BY United States Patent O 3,385,385 DRILL BIT Clement M. Kucera and Percy W. Schumacher, Jr.,

Houston, Tex., assignors to Reed Roller Bit Company, a corporation of Texas Filet] Apr. 1, 1966, Set. No. 539,388 17 Claims. (Cl. 175-374) ABSTRACT OF THE DISCLOSRE A roller bit including a roller cutter, said cutter having a circumfetntial web and inserts therein to allow penctration of the web into the formation being drilled with minimum contact between the web and the formation being drilled. This abstract is neither intended to define the invention of the application, which of course, is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.

This invention relates generally to drill bits and more particularly ,to drill bits for drilling earth formations.

The general object of the invention is to provide a new and improved bit which will efliciently drill hard formations and which will be found especially useful in drilling a large-diameter hole.

A specific object of the invention is to provide a bit having new and improved roller cutters which will cut kerfs in the formation and which will break the portions of the formation between the kerfs.

The preferred embodiment of the invention is illustrated by the accompanying drawings wherein:

FIGURE 1 is a plan view of the cutter end of a drill bit embodying the invention;

FIGURE 2 is a fragmentary sectional view of one embodiment of the roller cutter in engagement with the formation being cut;

FIGURE 3 is a fragmentary sectional view of a portion of the cutter illustrating another embodiment;

FIGURE 4 is a fragmentary sectional view of a portion et the cutter illustrating another embodiment;

FIGURE 5 is a diagrammatic view of a web of one of the cutters illustrating the mounting of the hardmetal inserts therein and the recesses between the inserts;

FIGURE 6 is a perspective view of the cutter illustrating the relative positions of the hard-metal inserts; and

FIGURE 7 is a sectional elevation of the cutter illustrating its mounting in the head.

The drill bit as shown in FIGURE 1 is provided with a head 10 which has a suitable means (not shown) for connecting the head to the drill string or other device which is to support and rotate the head. Attached to the cutting side of the head 10 are a plurality of frustoconical roller cutters Il, each of which is rotatably mounted on the head 10. The axis of each of the cutters 11 extends inwardly and away from the head 10 in a direction toward the longitudinal axis or center of rotation of the head 10. The larger-diameter base 12 of each cutter 11 is the outermost portion of the cutter with respect to the axis of rotation of the head 10.

Each of the cutters 11 is designed to cut at least two kerfs or grooves in face of the formation being cut. Referring to the form of cutter illustrated in FIGURE 2, the cutter 11 includes a body 13 with three outwardly extending circumferential webs or lands 14, 15 and 16. The body 13 has an internal shape suitable for rotational mounting to head 10. A plurality of hardened crushing inserts 17, such as tungsten carbide inserts, are set in each of the webs. The inserts 17 are alternately set at an angle to each side of the outward extension of the web. With this projection et the inserts and with the sides of 3,385,385 Patented May 28, 1968 each of the webs being generally parallel to the axis of the head 10, the contact between the web and the formation being cut is minimized to minimize the Wear on the webs. The inserts 17, therefore, may be set to ont a clearance for their web.

Each of the webs 14, 15 and 16 has a scalloped configuration to further minimize the contact between the web and the formation being drilled. This configuration is formed by the recesses 18 or concavities in the side of the webs opposite each insert 17. The recesses 18 in the web 14 are best illustrated in FIGURE 5 which schematically shows a partial layout of the outer edge of web 14 and the inserts 17.

In the form of cutter illustrated in FIGURE 2, the body 13 includes the formation breaking webs 19 and 20. These webs function t0 assist in breaking uncut portions of the formation between the kerfs or grooves which are cut into the formation. Additionally, a web 21 extends from the body 13 around its inner circumference. The web 21 functions t0 assist in breaking the portion of the formation remaining between the circular kerfs or grooves cut by the inserts on web 16. If desired, each of the webs 19, 20 and 21 may be cut to provide a plurality of teeth.

Another form of cutter 22 is shown in FIGURE 3 which is substantially similar to the cutter 11 shown in FIGURE 2. The cutter 22 includes the body 23 having a suitable interna] shape for rotational mounting to drill bit head 10 and includes at least two outwardly extending circumferential webs 24 and 25, each containing hardmetal inserts 26 similar to the construction of cutter 11. The cutter 22 provides a plurality of hard-metal inserts 27 in the body 23 between the webs 24 and 25 to assist in breaking loose the formation between the kerfs or grooves cut by the inserts 26 on the webs 24 and 25.

The other for-m illustrated in FIGURE 4 is the cutter 28 which includes a body 29 and at least two outwardly extending circumferential webs 30 and 31 with hard-metal inserts 32. The cutter 28 is identical with the cutters 11 and 22 except that it does not include any structure between the webs 30 and 31 to assist in breaking the remaining formation between the circular grooves cut by the inserts 32.

Referring to FIGURE 6, a perspective view of the cutter 11, illustrated in FIGURE 2 and its cutter support 34, is shown. A detailed sectional view of the cutter assembly, illustrated in FIGURE 6, is shown in FIG- URE 7. The cutter assembly 35, illustrated in FIGURE 7, is shown comprising a cutter support 36 having an inner support leg 37 and an outer support leg 38 spaced from said inner support leg. The inner support leg 37 has a hole 39 therethrough, and the outer support 38 has a hole 40 therethrough. A bearing journal 41 extends between the support legs 37 and 38 and has a roller race 42, a roller race 43, an outer roller race 44 and a hall race 45. A cutter 46, similar to cutter 11 in FIGURE 6, is provided with an inner roller race 47, an outer roller race 48 and a bail race 49. Roller bearings 50 are provided in the outer roller raceways; roller bearings 51 are provided in the inner roller raceways; and, bail bearings 52 are provided in the ball bearing raceways. The journal 41 has a bore 53 extending axially therethrough and a bail loading hole 54 extending from the bore 53 through the ball raceway 45 so that the halls 52 may be installed in the raceway. When a full complement of hall bearings 52 has been supplied to the raceway, a hall retaining plug 55 is inserted into the ball loading hole 54 and a snap ring 56 frictionally retains the ball retaining plug in place in the journal.

The hole 39 in the inner support leg 37 and the hole 40 in the outer support leg 38 are aligned. A bushing 57 is supplied within the hole 39 and a bushing 58 is supplied Witbin the hole 40. The bushing 58 has a slot 59, and a roll pin 60 is provided within the slot 59 and in the support 38 to prevent the bushing 58 from turning about its axis. A bearing pin 61 extends through the bushings 57, 58 and the journal 41, is retained in place by means of a cap screw 62, which is inserted into the support 37 through the bushing 57 and the pin 61, and is threaded into the hole 63.

The outer end of the cutter 46 has a counterbore 64 therein adjacent to the roller race 48, and a seal 65 is pressed or otherwise secured within said counterbore. The other end of the cutter 46 has a counterbore 66 into which is presscd or otherwise secured a seal 67. The outer portion of the journal 41 has a cylindrical section with an axial projection or boss 68 extending therefrom. This axial projection has a radially inwardly facing fiat surface 69. The journal 41 also has an inner cylindrical portion 70 which has an axial projection or boss 71, which projection has a radially inwardly facing fiat surface 72. The lower portion of the inner support 37 has a fiat 73 thereon. The lower portion of outer support 38 also has a fiat 74 thereon.

Thus, when the journal 41 is installed between the supports 37 and 38, the fiat surface 69 of the journal 41 is located by and registers with the fiat surface 74 of the outer support 38, and the fiat surface 72 of the journal 41 is located by and registers With the fiat 74 of the lower portion of support 37. In this manner, the journal is accurately located and the flats just described prevent torque -being applied to the pin 62 during operation of the drill bit. This arrangement of the flats also prevents the journal 41 from turning about its own axis during the drilling operation.

As can be seen in FIGURE 7, the disposition of the cutter 46 on the journal 41 and the positioning of the journal 41 between the supports 37 and 38 provide a gap 75 between the outer face of the cutter 46 and the inner face of the outer support 38. The surfaces of the cutter 46 in the support 38 define a substantially parallel gap. The arrangement of the gap so described tends to alleviate the accumulation of cuttings between the cutter and its associated support in order to keep detritus from abrading away the outer seal 65. As will also be apparent, as the cutter rotates, the seal, being pressed or tackwelded into the cutter, also rotates and as a given portion of the seal 65 approaches the bottom of the bore hole being drilled, it leaves the cutter support 38 and is exposed to the exterior of the bit. With this arrangement the trappngs of cuttings or detritus between the bit and its associated support is alleviated. A similar gap 76 is provided between the inner end of the cutter 46 and the inner cutter support 37 for the purpose just described.

The surface 77 of the cutter support 36, which may be made of a steel casting or the like, may be milled at various angles With respect to the rotating axis of the cutter, so that it can be mounted, as by welding, to the bottom of the bit head in accordance with the bottom hole configuration desired.

The mounting of the cutter 46 as described allows the cutter to rotate freely when in engagement with a formation, and rotation of the bit head causes each of the cutters to rotate therewith while rotating on the axis of the pin 61 to cut kerfs in the formation. The parts of the formation between the kerfs are broken out in relatively large pieces to complete the boring with the drill bit of the present invention.

A drill bit using the kerf producing cutters of the present invention will be found particularly useful in cutting large-diameter holes. It is particularly advan tageous since not all of the formation removed has to be out. The material between kerfs often breaks out without any assistance and readily breaks when contacted by the teeth 19, 20 and 21 of cutter 11 or the inserts 27 of cutter 22.

The drill bit of the present invention has proven to be particularly suitable for raise boring or horizontal tunneling since a large portion of the formation removed does not have to be out, and in such applications the formation material may be readily removed from the bore in much larger pieces.

As can be seen, the arrangement and spacing of the webs on the cutters is such -that the formation is not apt to hall up the cutters or to clog them with formation cuttings since the groove between the webs is relatively wide and may be from one-half inch to more than one inch wide. The depth of the groove between the webs is preferably at least one half inch. The ridges of uncut formation remaining between the kerfs produced by the cutters of the invention may be on the order of threefourth inch in width or more.

Also, the webs of two or more cutters cutting in the same path may have dilerent numbers of hardened cutting elements from one cutter to the other so that the inserts or cutting elements of the following cutter do not fall into the impressions made by the preceding cutter, whereby a non-trackng pattern is produced upon the formation at the bottom of the kerf.

The arrangement and spacing of the webs and the cutters are such that enhanced drilling performance is pro duced by the bit of the invention.

Thus, the drill bit of the present invention has a greatly improved drilling efliciency, and the body and webs of the cutters are protected from excessive contact with the formation to mnimize wear.

The foregoing discl0sure and description of the invention are illustrative and explanatory tbereof, and various changes in the size, shape and materials, as well as in the details of the illustrated construction, may be made within the scope of the appended claims without departing from the spirit of the invention.

What is claimed is:

1. A roller bit comprising a head,

a plurality of substantially frusto-conical roller cutters rotatably mounted on said head, the axes of rotation of said cutters extending inwardly and away from said head toward the longitudinal axis of said head, the base end of said cutters being outermost,

each of said cutters having at least two circumferential webs extending outwardly, and

a plurality of hardened cutting elements positioned in each of said webs whereby on rotation of said head each of said cutters cuts at least two circular kerfs in the formation engaged by said cutters,

said web is alternately recessed on opposite sides thereof and cutting elements inserted into said web opposite each recess,

said cutting elements are inserted in said web at an inclination outwardly and away from its opposite recess to cut a kerf having a greater width than said web.

2. A roller bit comprising a head,

3 plurality of substantially frusto-conical roller cutters rotatably mounted on said head, the axes of rotation of said cutters extending inwardly and away from said head toward the longitudinal axis of said head, the base end of said cutters being outermost,

each of said cutters having at least two crcumferential webs, and

two rows of circumferentially spaced inserts in each of said webs,

said inserts being positioned at an angle to said webs whereby contact between the formation being cut and said webs is minimized.

3. A roller bit according to claim 2, wherein said means includes cutting elements positioned in said cutter between said webs.

4. A roller bit according to claim 2 wherein the webs of diterent cutters cutting in the same paths have diterent numbers of hardened cutting elements so that a nontracking pattern is produced on the bottom of the kerf.

5. A roller bit according to claim 2 wherein a plurality of the said cutters have webs cutting matching paths,

the Webs of one cutter containing a diflerent number of hardened cutting elements from another cutter web cutting the same path.

6. A roller bit according to claim 2 including formation breaking means on said cutters between said webs,

said webs projecting outwardly beyond said formation breaking means.

7. A roller bit according to claim 4 wherein said formation breaking means comprises teeth projecting from said cutters betwen said webs.

8. A roller bit according to claim 4 wherein said formation breaking means comprises a plurality of inserts positioned in said cutter between said webs.

9. A roller bit according to claim 2 wherein said cutters are spaced at unequal distances from the longitudinal axis of said head.

10. A roller bit comprising a head,

a plurality of snbstantially fruste-conical roller cutters rotatably mounted on said head, the axes of rotation of said cutters extending inwardly and away from said head toward the longitudinal axis of said head, the base and of said cutters being outermost,

each of said cutters having a body and a circumferential web extending outwardly therefrom, and

a plurality of hardened cutting inserts,

said inserts being positioned in said web With their outermost portions extending outwardly frorn said web and their innermost portions terminating in said web exteriorly of said body,

said inserts being positioned at an angle to said web whereby contact between the formation being out and said web is minimized.

11. A roller bit comprising a head, and

a plnrality of roller cutters mounted on said head,

at least one of said cutters having a body and a circumferential web extending outwardly therefrom, and

a plurality of inserts positioned in said web at an angle thereto With their outermost portions extending outwardly from said web and their innermost portions terminating in said web exteriorly of said body where by said inserts are so arranged that as the web penctrates into the formation being drilled, contact between the web and the formation is minimized.

12. A roller bit comprising a head, and

a plurality of roller cutters mounted on said head,

at least one of the cutters having a body and a circumferential web extending outwardly therefrom and a plurality of hardened inserts positioned in said web at an angle thereto with their outermost portions extending outwardly from said web and their innerteeth engage said formation only after said kerfs have been at least partially out by said cutting elements in said web.

14. A roller cutter having a body,

a circumferential web extending outwardly from said body, and

a plurality of inserts positioned in said web at an angle thereto with their outermost portions extending outwardly from said web and their innermost portions terminating in said web exteriorly of said body whereby said web is capable of penetrating the formation being drilled and contact between said web and the formation is minimized.

15. A roller cutter having a body,

a circumferential web extending outwardly from said body, and

at least one row of inserts positioned in said web at an angle thereto with their outermost portions extending outwardly from said web and their innermost portiens terminating in said web exteriorly of said body whereby contact between said web and the formation being cut is minimized.

16. A roller cutter having a circumfcrential web, and

two rows cf circumferentially spaced inserts in said web,

the inserts of one of said rows being staggered with respect to the inserts of the other of said rows,

said web having recesses in its opposite sides between said inserts.

17. A roller cutter having a circumferential web, and

two rows of circumferentially spaced inserts in said web,

the inserts on one of said rows being staggered with respect to the inserts of the other of said rows and being positioned at an angle thereto.

References Cited UNITED STATES PATENTS 2,177,332 10/1939 Reed 175-378 2,482,263 9/1949 Goodwin 175-378 2,804,282 8/1957 Spengler 175-378 2,927,777 3/1960 Steen 175-378 2,990,025 6/1961 Talbert 175-378 X 2,998,857 9/1961 Deily 175-378 X 3,018,835 1/1962 Kucera 175-378 3,126,973 3/1964 Kiel 175-378 3,203,492 8/1965 Lichte 175-378 3,126,067 3/1964 Schumacher 175-374 NILE c. BYERS, IR., Primary Examiner. 

